Method for modifying a plant phenotype

ABSTRACT

The present invention relates generally to methods for generating plants having altered phenotypes, and to plants so generated and parts of these plants. More particularly, the present invention relates to a method for modifying a plant so as to produce a plant exhibiting an altered phenotype. Particularly useful altered phenotypes contemplated by the present invention include plants having altered tissue architecture. The present invention further contemplates genetic sequences capable of facilitating the modification of a phenotype of a plant and to sequences complementary thereto and to derivatives of the sequences. Plants and parts of plants, such as flowering and reproductive parts including seeds, also form part of the present invention. The ability to modify the phenotype of a plant may be useful for, inter alia, producing plants with more highly desired characteristics, such as delayed flowering, increased lateral branching, delayed senescence and the like.

This is the U.S. National Phase under 35 U.S.C. § 371 of InternationalApplication PCT/AU01/01587, filed Dec. 7, 2001, which claims priority ofAustralian provisional application No. PR2011/00, filed Dec. 8, 2000.Each of the above applications are incorporated herein by reference intheir entirety.

FIELD OF THE INVENTION

The present invention relates generally to methods for generating plantshaving altered phenotypes, and to plants so generated and parts of theseplants. More particularly, the present invention relates to a method formodifying a plant so as to produce a plant exhibiting an alteredphenotype. Particularly useful altered phenotypes contemplated by thepresent invention include plants having altered tissue architecture. Thepresent invention further contemplates genetic sequences capable offacilitating the modification of a phenotype of a plant and to sequencescomplementary thereto and to derivatives of the sequences. Plants andparts of plants, such as flowering and reproductive parts includingseeds, also form part of the present invention. The ability to modifythe phenotype of a plant may be useful for, inter alia, producing plantswith more highly desired characteristics, such as delayed flowering,increased lateral branching, delayed senescence and the like.

BACKGROUND OF THE INVENTION

Bibliographic details of the publications referred to by author in thisspecification are collected at the end of the description.

Reference to any prior art in this specification is not, and should notbe taken as, an acknowledgment or any form of suggestion that this priorart forms part of the common general knowledge in Australia or any othercountry.

Recombinant DNA technology is now an integral part of strategies togenerate genetically modified eukaryotic cells. The past decade of plantmolecular biology has seen the identification and cloning of thousandsof genetic sequences, of both genomic and cDNA origin, from hundreds ofplant species. With the recent development of advanced rapid techniquesfor cloning and sequencing and the completion or near-completion of thesequencing of entire genomes, such as for example for Arabidopsis andrice, attention has been re-focused on to the characterization ofisolated sequences and the elucidation of their in vivo function.

One approach for carrying out these studies involves the production of arange of mutant plant lines exhibiting loss-of-function orgain-of-function phenotypes, and the subsequent selection andcharacterization of the mutant phenotypes produced. Techniques areavailable for the genetic transformation of a number of plant speciesand for the modulation of expression of genetic sequences, such as bythe introduction of sense and/or antisense copies of particular geneticsequences.

In recent work leading up to the present invention, the inventors soughtto identify modified phenotypes having potential commercial interest. Inaccordance with the present invention, the inventors have now identifieda genetic sequence capable of modification of a plant's tissuearchitecture. The plants so generated exhibit commercially usefultraits.

SUMMARY OF THE INVENTION

Throughout this specification, unless the context requires otherwise,the word “comprise”, or variations such as “comprises” or “comprising”,will be understood to imply the inclusion of a stated element or integeror group of elements or integers but not the exclusion of any otherelement or integer or group of elements or integers.

Nucleotide and amino acid sequences are referred to by a sequenceidentifier number (SEQ ID NO:). The SEQ ID NOs: correspond numericallyto the sequence identifiers <400>1, <400>2, etc. A sequence listing isprovided after the claims.

The present invention provides a method for generating plants and partsof plants having modified phenotypes. Particularly useful modifiedphenotypes contemplated by the present invention include plants havingaltered tissue architecture. Examples of altered tissue architectureinclude but are not limited to changes in cell shape to create largermore elongated structures, or to create smaller more compact structures;changes in cellular development leading to diversion of developmentalpathways and concomitant absence of some tissues; changes in cellnumbers leading to smaller or larger tissues, all of which changesultimately lead to a modified phenotype such as, for example, shorter orlonger stem tissue, reduced or increased lateral branching, preferentialgrowth of inflorescence-bearing tissues rather than leaf-bearingtissues, decreased height and increased compactness of plant shape. Aphenotype incorporating any one or more of these changes is referred toherein as “plentiful”.

The present invention further contemplates genetic sequences capable offacilitating the modification of a phenotype of a plant and to sequencescomplementary thereto and to derivatives of these sequences. Thepreferred nucleotide sequence of the present invention is also referredto herein as “plentiful” and comprises the nucleotide sequence as setforth in SEQ ID NO:1. The proteinaceous product of plentiful comprisesan amino acid sequence as set forth in SEQ ID NO:2.

Plants and parts of plants, such as flowering and reproductive partsincluding seeds, also form part of the present invention. The ability tomodify the phenotype of a plant may be useful for, inter alia, producingplants with more highly desired characteristics, such as delayedflowering, increased lateral branching, delayed senescence and the like.

Accordingly, one aspect of the present invention contemplates a methodfor generating a plant with a modified plant phenotype, said methodcomprising introducing into the genome of one or more cells of a plantor one or more cells of a parent of a first-mentioned plant a nucleicacid molecule which, when expressed in cells of a plant, results in thephenotype of the cells being modified relative to cells not expressingsaid nucleic acid molecule.

In a particularly preferred embodiment, the present inventioncontemplates a method for modulating plant tissue architecture, saidmethod comprising introducing into the genome of one or more cells of aplant or one or more cells of a parent of a first-mentioned plant anucleic acid molecule capable of effecting an alteration to cellular ortissue architecture and then regenerating a plant from said one or morecells.

Another aspect of the present invention is directed to a method forgenerating a plant with a modified plant phenotype, said methodcomprising introducing into the genome of one or more cells of saidplant or one or more cells of a parent of said first-mentioned plant anucleic acid molecule comprising a nucleotide sequence encoding or asequence complementary to a nucleotide sequence encoding an amino acidsequence set forth in SEQ ID NO:2 or a derivative thereof including anamino acid sequence having at least about 75% sequence identity with SEQID NO:2 after optimal alignment and then regenerating a plant from saidplant cells to produce a plant with said altered phenotype andoptionally generating a progeny plant with said altered phenotype fromsaid regenerated plant.

A related aspect of the present invention is directed to a method forfacilitating the modification of a plant phenotype, said methodcomprising introducing into the genome of one or more cells of a saidplant or one or more cells of a parent of said first-mentioned plant anucleic acid molecule comprising a nucleotide sequence homolog encodingor a sequence complementary to a nucleotide sequence encoding an aminoacid sequence set forth in SEQ ID NO:2 or a derivative thereof includingan amino acid sequence having at least about 75% identity to SEQ ID NO:2after optimal alignment.

A further aspect of the present invention is directed to a method foraltering the phenotype of a plant, said method comprising introducinginto the genome of one or more cells of said plant or one or more cellsof a parent of said first-mentioned plant a nucleic acid moleculecomprising a nucleotide sequence substantially as set forth in SEQ IDNO:1 or a variant or homolog thereof including a nucleotide sequencehaving at least about 75% identity to SEQ ID NO:1 after optimalalignment or a nucleotide sequence capable of hybridizing to SEQ ID NO:1or its complementary form under low stringency conditions.

Yet another aspect of the present invention is directed to a method foraltering the phenotype of a plant, said method comprising introducinginto the genome of one or more cells of a plant or one or more cells ofa parent of said first-mentioned plant a chimeric genetic constructcomprising a nucleotide sequence substantially as set forth in SEQ IDNO:1 or a variant or homolog thereof including a nucleotide sequencehaving at least about 75% identity to SEQ ID NO:1 after optimalalignment or a nucleotide sequence capable of hybridizing to SEQ ID NO:1or its complementary form under low stringency conditions.

Still another aspect of the present invention is directed to a chimericgenetic construct comprising a nucleic acid molecule comprising anucleotide sequence substantially as set forth in SEQ ID NO:1 or avariant or homolog thereof including a nucleotide sequence having atleast about 75% identity to SEQ ID NO:1 after optimal alignment or anucleotide sequence capable of hybridizing to SEQ ID NO:1 or itscomplementary form under low stringency conditions.

Even yet another aspect of the present invention is directed to a vectorin the form of a chimeric construct comprising a nucleic acid moleculehaving a nucleotide sequence substantially as set forth in SEQ ID NO:1or a variant or homolog thereof including a nucleotide sequence havingat least about 75% identity to SEQ ID NO:1 after optimal alignment or anucleotide sequence capable of hybridizing to SEQ ID NO:1 or itscomplementary form under low stringency conditions.

Another aspect of the present invention provides a method for generatinga plant with altered tissue architecture, said method comprisingintroducing into the genome of one or more cells of said plant or one ormore cells of a parent of said first-mentioned plant a nucleic acidmolecule comprising a nucleotide sequence encoding or a sequencecomplementary to a nucleotide sequence encoding an amino acid sequenceset forth in SEQ ID NO:2 or a derivative thereof including an amino acidsequence having at least about 75% similarity to SEQ ID NO:2 afteroptimal alignment and then regenerating a plant from said plant cells toproduce a plant with said altered tissue architecture and optionallygenerating a progeny plant with said altered tissue architecture fromsaid regenerated plant.

In a related aspect, the present invention provides a method formodifying plant tissue architecture, said method comprising introducinginto the genome of one or more cells of said plant or one or more cellsof a parent of said first-mentioned plant a nucleic acid moleculecomprising a nucleotide sequence encoding, or a sequence complementaryto a nucleotide sequence encoding, an amino acid sequence set forth inSEQ ID NO:2 or a derivative thereof including an amino acid sequencehaving at least about 75% identity to SEQ ID NO:2 after optimalalignment.

A further aspect of the present invention contemplates a method formodifying plant tissue architecture, said method comprising introducinginto the genome of one or more cells of said plant or one or more cellsof a parent of said first-mentioned plant a nucleic acid moleculecomprising a nucleotide sequence substantially as set forth in SEQ IDNO:1 or a variant or homolog thereof including a nucleotide sequencehaving at least about 75% identity to SEQ ID NO:1 after optimalalignment or a nucleotide sequence capable of hybridizing to SEQ ID NO:1or its complementary form under low stringency conditions.

Yet another aspect of the present invention provides a transfected ortransformed cell, tissue, or organ which comprises a nucleotide sequencesubstantially as set forth in SEQ ID NO:1 or a variant or homologthereof including a nucleotide sequence having at least about 75%identity to SEQ ID NO:1 after optimal alignment or a nucleotide sequencecapable of hybridizing to SEQ ID NO:1 or its complementary form underlow stringency conditions and/or is capable of producing an amino acidsequence set forth in SEQ ID NO:2 or a derivative thereof including anamino acid sequence having at least about 75% sequence identity with SEQID NO:2 after optimal alignment.

Still another aspect of the present invention provides a method formodifying plant tissue architecture, said method comprising introducinginto the genome of one or more cells of said plant or one or more cellsof a parent of said first-mentioned plant a vector comprising a chimericgenetic construct comprising a nucleotide sequence substantially as setforth in SEQ ID NO:1 or a variant or homolog thereof including anucleotide sequence having at least about 75% identity to SEQ ID NO:1after optimal alignment or a nucleotide sequence capable of hybridizingto SEQ ID NO:1 or its complementary form under low stringency conditionsand then regenerating a plant from said plant cells to produce a plantwith modified tissue architecture.

Even still another aspect of the present invention provides agenetically modified plant cell or multicellular plant or progenythereof or parts of said transgenic plant having an altered phenotypecompared to its non-transformed equivalent, wherein said transgenicplant comprises the nucleotide sequence substantially as set forth inSEQ ID NO:1 or a variant or homolog thereof including a nucleotidesequence having at least about 75% identity to SEQ ID NO:1 after optimalalignment or a nucleotide sequence capable of hybridizing to SEQ ID NO:1or its complementary form under low stringency conditions.

Even yet another aspect of the present invention contemplates agenetically modified plant cell or multicellular plant or progeny orparts thereof comprising a nucleic acid molecule comprising a nucleotidesequence encoding or a sequence complementary to a sequence encoding anamino acid sequence set forth in SEQ ID NO:2 or a derivative thereof oran amino acid sequence having at least about 75% sequence identity withSEQ ID NO:2 after optimal alignment.

Another aspect of the present invention provides a plant cell ormulticellular plant or progeny or parts thereof wherein said cell,plant, progeny or part thereof exhibits altered tissue architecturecompared to its non-transformed equivalent.

A further aspect of the present invention is directed to the use of anucleic acid molecule comprising a nucleotide sequence substantially asset forth in SEQ ID NO:1 or a variant or homolog thereof including anucleotide sequence having at least about 75% identity to SEQ ID NO:1after optimal alignment or a nucleotide sequence capable of hybridizingto SEQ ID NO:1 or its complementary form under low stringency conditionsin the manufacture of a transgenic plant having tissues with alteredphenotype.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a photographic representation of a multi-tissue Northern blotanalysis displaying the expression pattern of the plentiful gene inwild-type Arabidopsis. Total RNA (10) μg was electrophoresed andtransferred to a nylon membrane before hybridizing to a ³²P-labeledplentiful EST probe (gene probe). The membrane was then stripped andrehybridized to a ribosomal probe (rRNA probe).

FIG. 2 is a photographic representation of Northern analysis of twoindependent plentiful transgenic lines and three separate wild-typesamples. Total RNA (10 μg) from 2-week seedlings was electrophoresed andtransferred to a nylon membrane before hybridizing to a ³²P-labeledplentiful EST probe (gene probe). The membrane was then stripped andrehybridized to a ribosomal probe (rRNA probe).

FIG. 3 is a photographic representation of Northern analysis ofdifferent tissues of the transformed plentiful line 116-5D (M) andwild-type phenotype non-transformed segregant lines (WT). Total RNA (10μg) was electrophoresed and transferred to a nylon membrane beforehybridizing to a ³²P-labeled plentiful EST probe (gene probe). Themembrane was then stripped and rehybridized to a ribosomal probe (rRNAprobe).

FIGS. 4A and B compare photographic representations of Southern analysisof (FIG. 4A) CaMV35S and (FIG. 4B) plentiful fragment pattern fornon-transformed wild-type (WT) and two transformed lines displaying theplentiful phenotype (Lines 4B and 5D), each digested with restrictionenzymes EcoRI, HindIII and SalI, as shown. Size markers are alsoindicated. The results provide evidence for independent transformationevents.

FIG. 5 is a photographic representation of Southern analysis, showing arestriction digest of the plentiful EST in the PRL-2 library plasmid,pZL1. Plasmid DNA (1 μg) was digested separately with EcoRI, HindIII andSalI, the same enzymes used in the Southern blot shown in FIG. 4, andelectrophoresed on a 0.8% v/v agarose gel. Size markers are alsoindicated. Refer to Example 6 for further discussion.

FIGS. 6A-D are photographic representations showing the differentphenotypes of wild-type Arabidopsis (Columbia) plants, compared to theplentiful phenotypes of the transformed plants of the present invention:FIG. A shows wild-type inflorescence; FIG. B shows plentiful phenotypeinflorescence head; FIG. C shows non-transformed 25-day-old segregant onthe left of the picture, and 49-day-old plentiful phenotype on the rightof the picture, at similar developmental stages; and FIG. D showswild-type 31-day-old phenotype on the left, and 64-day-old plentifulphenotype on the right of the picture.

FIGS. 7A-E are photographic representations showing mature plentifulphenotypes and wild-type Arabidopsis. FIG. A shows Plentiful phenotype(left) and wild-type Arabidopsis plants at 50 days; FIG. B showsPlentiful phenotype 11 days later at end of reproductive phase; FIG. Cshows close up image of rosette leaves of plentiful phenotype (left) andwild-type Arabidopsis (right) at 50 days; white arrows indicate regionsof severe senescence; FIG. D shows close up of siliques of plentifulphenotype; and FIG. E shows close up of siliques of wild-type phenotype.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is predicated in part on the identification ofnucleic acid molecules capable of modifying the cellular matrix of aplant to produce plant cells and tissues which, upon regeneration, yieldwhole plants exhibiting altered characteristics and with desirabletraits, and more particularly having tissues, organs or reproductiveparts exhibiting altered architecture.

Accordingly, one aspect of the present invention contemplates a methodfor generating a plant with a modified plant phenotype, said methodcomprising introducing into the genome of one or more cells of a plantor one or more cells of a parent of said first-mentioned plant a nucleicacid molecule which, when expressed in cells of a plant, results in thephenotype of the cells being modified relative to cells not expressingsaid nucleic acid molecule.

Reference herein to a “plant” includes both monocotyledonous plants anddicotyledonous plants. Particularly useful plants are food crops such aswheat, rice, barley, soybean and sugar cane, and other non-foodcommercial crops such as cotton. Flower and ornamental crop plants,including, for example, rose, carnation, petunia, lisianthus, lily,iris, tulip, freesia, delphinium, limonium and pelargonium, are alsoencompassed within the scope of the invention. The instant inventionfurther extends to forestry crops cultivated for wood-chips for pulp andpaper production, or for timber production for the manufacture of woodenarticles such as furniture. That is, all plants may fall within thescope of the present invention, including woody species. In accordancewith this aspect of the present invention, a plant is first regeneratedfrom the cell or cells into which the nucleic acid molecule has beenintroduced.

In a particularly preferred embodiment, the present inventioncontemplates a method for modulating plant tissue architecture, saidmethod comprising introducing into the genome of one or more cells of aplant or one or more cells of a parent of said first-mentioned plant anucleic acid molecule capable of effecting an alteration to cellular ortissue architecture and then regenerating a plant from said one or morecells.

Cellular and tissue architecture determine such phenotypic traits assize and shape of particular plant cells and tissues and hence of wholeplantlets and adult plants. Modulation of a plant's cellular or tissuearchitecture may result in, for example, changes in cell shape to createlarger more elongated structures, or to create smaller more compactstructures; changes in cellular development leading to diversion ofdevelopmental pathways and concomitant absence of some tissues; changesin cell numbers leading to smaller or larger tissues, all of whichchanges ultimately lead to a modified phenotype such as, for example,shorter or longer stem tissue, reduced or increased lateral branching,preferential growth of inflorescence-bearing tissues rather thanleaf-bearing tissues, decreased height and increased compactness ofplant shape, to mention but a few.

The ability to control the modification of particular traits, singly orin concert, may provide the possibility to generate designer plants,exhibiting appropriate desired characteristics. Without wishing to limitthe generality of the present invention, such modification of a plant'scellular or tissue architecture may be effected by modulation of adevelopmental or developmentally-regulated gene, leading to analteration in the expression of one or more substrates or enzymes in arelevant biochemical pathway.

Accordingly, another aspect of the present invention is directed to amethod for generating a plant with a modified phenotype, said methodcomprising introducing into the genome of one or more cells of saidplant or one or more cells of a parent of said first-mentioned plant anucleic acid molecule comprising a nucleotide sequence encoding or asequence complementary to a nucleotide sequence encoding an amino acidsequence set forth in SEQ ID NO:2 or a derivative thereof including anamino acid sequence having at least about 75% sequence identity with SEQID NO:2 after optimal alignment and then regenerating a plant from saidplant cells to produce a plant with said altered phenotype andoptionally generating a progeny plant with said altered phenotype fromsaid regenerated plant.

A related aspect of the present invention is directed to a method forfacilitating the modification of a plant phenotype, said methodcomprising introducing into the genome of one or more cells of a saidplant or one or more cells of a parent of said first-mentioned plant anucleic acid molecule comprising a nucleotide sequence encoding or asequence complementary to a nucleotide sequence encoding an amino acidsequence set forth in SEQ ID NO:2 or a derivative thereof including anamino acid sequence having at least about 75% identity to SEQ ID NO:2after optimal alignment.

By “derivative” is meant a polypeptide that has been derived from thebasic sequence by modification, for example, by conjugation orcomplexing with other chemical moieties or by post-translationalmodification techniques as would be understood in the art. The term“derivative” also includes within its scope alterations that have beenmade to a parent sequence including additions, or deletions that providefor functionally-equivalent molecules. Accordingly, the term“derivative” encompasses molecules that affect a plant's phenotype inthe same way as does the parent an amino acid sequence from which it wasgenerated. Also encompassed are polypeptides in which one or more aminoacids have been replaced by different amino acids. It is well understoodin the art that some amino acids may be changed to others with broadlysimilar properties without changing the nature of the activity of thepolypeptide (conservative substitutions) as described hereinafter. Theseterms also encompass polypeptides in which one or more amino acids havebeen added or deleted, or replaced with different amino acids.

“Polypeptide”, “peptide” and “an amino acid sequence” are usedinterchangeably herein to refer to a polymer of amino acid residues andto variants and synthetic analogues thereof. Thus, these terms apply toamino acid polymers in which one or more amino acid residues is asynthetic non-naturally-occurring amino acid, such as a chemicalanalogue of a corresponding naturally-occurring amino acid, as well asto naturally-occurring amino acid polymers.

The term “derivative” also encompasses fragments. A “fragment”, as usedherein, means a portion or a part of a full-length parent polypeptide,which retains the activity of the parent polypeptide. As used herein,the term “biologically-active fragment” includes deletion mutants andsmall peptides, for example, of at least 10, preferably at least 20 andmore preferably at least 30 contiguous amino acids, which comprise theabove activity. Peptides of this type may be obtained through theapplication of standard recombinant nucleic acid techniques orsynthesized using conventional liquid or solid phase synthesistechniques. For example, reference may be made to solution synthesis orsolid phase synthesis as described, for example, in Chapter 9 entitled“Peptide Synthesis” by Atherton and Shephard which is included in apublication entitled “Synthetic Vaccines” edited by Nicholson andpublished by Blackwell Scientific Publications. Alternatively, peptidescan be produced by digestion of an amino acid sequence of the inventionwith proteinases such as endoLys-C, endoArg-C, endoGlu-C andstaphylococcus V8-protease. The digested fragments can be purified by,for example, high performance liquid chromatographic (HPLC) techniques.Any such fragment, irrespective of its means of generation, is to beunderstood to be encompassed by the term “derivative” as used herein.

In another aspect of the invention, there is provided a method foraltering the phenotype of a plant, said method comprising introducinginto the genome of one or more cells of said plant or one or more cellsof a parent of said first-mentioned plant a nucleic acid moleculecomprising a nucleotide sequence substantially as set forth in SEQ IDNO:1 or a variant or homolog thereof including a nucleotide sequencehaving at least about 75% sequence identity to SEQ ID NO:1 after optimalalignment or a nucleotide sequence capable of hybridizing to SEQ ID NO:1or its complementary form under low stringency conditions.

The terms “variant” and “homolog” refer to nucleotide sequencesdisplaying substantial sequence identity with a reference nucleotidesequences or polynucleotides that hybridize with a reference sequenceunder stringency conditions that are defined hereinafter. The terms“nucleotide sequence”, “polynucleotide” and “nucleic acid molecule” maybe used herein interchangeably and encompass polynucleotides in whichone or more nucleotides have been added or deleted, or replaced withdifferent nucleotides. In this regard, it is well understood in the artthat certain alterations inclusive of mutations, additions, deletionsand substitutions can be made to a reference nucleotide sequence wherebythe altered polynucleotide retains the biological function or activityof the reference polynucleotide. The term “variant” also includesnaturally-occurring allelic variants.

The extent of homology may be determined using sequence comparisonprograms such as GAP (Deveraux et al., 1984). In this way, sequences ofa similar or substantially different length to those cited herein mightbe compared by insertion of gaps into the alignment, such gaps beingdetermined, for example, by the comparison algorithm used by GAP, as isfurther discussed below.

Homologous sequences will generally hybridize under particular specifiedconditions. The term “hybridization” denotes the pairing ofcomplementary nucleotide sequences to produce a DNA-DNA hybrid or aDNA-RNA hybrid. Complementary base sequences are those sequences thatare related by the base-pairing rules. In DNA, A pairs with T and Cpairs with G. In RNA U pairs with A and C pairs with G. In this regard,the terms “match” and “mismatch” as used herein refer to thehybridization potential of paired nucleotides in complementary nucleicacid strands. Matched nucleotides hybridize efficiently, such as theclassical A-T and G-C base pair mentioned above. Mismatches are othercombinations of nucleotides that do not hybridize efficiently.

The extent of hybridization that may be displayed by homologoussequences depends on the conditions of, for example, temperature, ionicstrength, presence or absence of certain organic solvents, under whichhybridization and washing procedures are carried out. The higher thestringency, the higher will be the degree of complementarity betweenimmobilised target nucleotide sequences and the labelled probepolynucleotide sequences that remain hybridized to the target afterwashing. “High stringency conditions” refers to temperature and ionicconditions under which only nucleotide sequences having a high frequencyof complementary bases will hybridize. The stringency required isnucleotidesequence dependent, and further depends upon the variouscomponents present during hybridization and subsequent washes, and thetime allowed for these processes. Generally, in order to maximize thehybridization rate, relatively low-stringency hybridization conditionsare selected: about 20 to 25° C. lower than the thermal melting point(T_(m)). The T_(m) is the temperature at which 50% of specific targetsequence hybridizes to a perfectly complementary probe in solution at adefined ionic strength and pH. Generally, in order to require at leastabout 85% nucleotide complementarity of hybridized sequences, highlystringent washing conditions are selected to be about 5 to 15° C. lowerthan the T_(m). In order to require at least about 70% nucleotidecomplementarity of hybridized sequences, moderately-stringent washingconditions are selected to be about 15 to 30° C. lower than the T_(m).Highly permissive (very low stringency) washing conditions may be as lowas 50° C. below the T_(m), allowing a high level of mis-matching betweenhybridized sequences. Those skilled in the art will recognize that otherphysical and chemical parameters in the hybridization and wash stagescan also be altered to affect the outcome of a detectable hybridizationsignal from a specific level of homology between target and probesequences.

Reference herein to “low stringency conditions” is generally determinedat 42° C. and includes and encompasses from at least about 0% v/v to atleast about 15% v/v formamide, and from at least about 1 M to at leastabout 2 M salt for hybridization, and at least about 1 M to at leastabout 2 M for washing conditions. Alternative stringency conditions maybe applied where necessary, such as: medium stringency, which includesand encompasses from at least about 16% v/v to at least about 30% v/vformamide, and from at least about 0.5 M to at least about 0.9 M saltfor hybridization, and at least about 0.5 M to at least about 0.9 M saltfor washing conditions, or high stringency, which includes andencompasses from at least about 31% v/v to at least about 50% v/vformamide, and from at least about 0.01 M to least about 0.15 M salt forhybridization, and at least about 0.01 M to at least about 0.15 M saltfor washing conditions.

Suitably, the variant or homolog has at least about 75%, preferably atleast about 80%, more preferably at least about 85%, more preferably atleast about 90% and still more preferably at least about 95% sequenceidentity to the nucleotide sequence set forth in SEQ ID NO:1 or itscomplementary form. Variants and homologs may also correspond toderivatives of an amino acid sequence as set forth in SEQ ID NO:2. Inone embodiment, derivatives have at least about 75%, preferably at leastabout 80%, more preferably at least about 85%, more preferably at leastabout 90% and still more preferably at least about 95% sequence identityto all or part of SEQ ID NO:2.

Terms used to describe sequence relationships between two or morenucleotide sequences or amino acid sequences include “referencesequence”, “comparison window”, “sequence identity”, “percentage ofsequence identity” and “substantial identity”. A “reference sequence” isat least 12 but frequently 15 to 18 and often at least 25 monomer units,inclusive of nucleotides and amino acid residues, in length. Because twopolynucleotides may each comprise (1) a sequence (i.e. only a portion ofthe complete polynucleotide sequence) that is similar between the twopolynucleotides, and (2) a sequence that is divergent between the twopolynucleotides, sequence comparisons between two (or more)polynucleotides are typically performed by comparing sequences of thetwo polynucleotides over a “comparison window” to identify and comparelocal regions of sequence similarity. A “comparison window” refers to aconceptual segment of at least 6 contiguous positions, usually about 50to about 100, more usually about 100 to about 150 in which a sequence iscompared to a reference sequence of the same number of contiguouspositions after the two sequences are optimally aligned. The comparisonwindow may comprise additions or deletions (i.e. gaps) of about 20% orless as compared to the reference sequence (which does not compriseadditions or deletions) for optimal alignment of the two sequences.Optimal alignment of sequences for aligning a comparison window may beconducted by computerized implementations of algorithms (GAP, BESTFIT,FASTA, and TFASTA in the Wisconsin Genetics Software Package Release7.0, Genetics Computer Group, 575 Science Drive Madison, Wis., USA) orby inspection and the best alignment (i.e. resulting in the highestpercentage homology over the comparison window) generated by any of thevarious methods selected. Reference also may be made to the BLAST familyof programs as for example disclosed by Altschul et al., 1997. Adetailed discussion of sequence analysis can be found in Unit 19.3 ofAusubel et al., 1998.

The term “sequence identity” as used herein refers to the extent thatsequences are identical on a nucleotide-by-nucleotide basis or an aminoacid-by-amino acid basis over a window of comparison. Thus, a“percentage of sequence identity” is calculated by comparing twooptimally aligned sequences over the window of comparison, determiningthe number of positions at which the identical nucleic acid base (e.g.A, T, C, G, I) or the identical amino acid residue (e.g. Ala, Pro, Ser,Thr, Gly, Val, Leu, Ile, Phe, Tyr, Trp, Lys, Arg, His, Asp, Glu, Asn,Gln, Cys and Met) occurs in both sequences to yield the number ofmatched positions, dividing the number of matched positions by the totalnumber of positions in the window of comparison (i.e. the window size),and multiplying the result by 100 to yield the percentage of sequenceidentity. For the purposes of the present invention, “sequence identity”will be understood to mean the “match percentage” calculated by theDNASIS computer program (Version 2.5 for windows; available from HitachiSoftware engineering Co., Ltd., South San Francisco, Calif., USA) usingstandard defaults as used in the reference manual accompanying thesoftware.

In accordance with the present invention, the nucleotide sequence setforth in SEQ ID NO:1 or a variant or homolog thereof or a nucleotidesequence capable of hybridizing to SEQ ID NO:1 or its complementary formunder low stringency conditions or a nucleotide sequence having at leastabout 75% sequence identity with SEQ ID NO:1 or its complementary formafter optimal alignment may be introduced into and optionally expressedin a recipient plant cell in order to create a desired phenotype.Phenotypes contemplated include but are not limited to increased lateralbranching, more plentiful growth of inflorescence-bearing stems, andmore plentiful inflorescences. A sequence complementary to the sequenceset forth in SEQ ID NO:1 or a variant or homolog thereof or a sequencehaving at least about 75% sequence identity therewith may result inprevention of expression of the introduced sequence via any one of anumber of processes known to those skilled in the art; for example,antisense suppression or sense suppression. Such down-regulation of geneexpression may result in decreased lateral branching or increased growthof the primary shoot such as may be desired for the generation of treessuitable for the timber industry.

The term “expression” is used in its broadest sense and includestransient, semi-permanent and stable expression, as well as inducible,tissue-specific, constitutive and/or developmentally-regulatedexpression. Stable, tissue-specific expression is preferred.

Accordingly, introduction of the polynucleotide of SEQ ID NO:1 or avariant or homolog thereof or a nucleotide sequence capable ofhybridizing to SEQ ID NO:1 or its complementary form under lowstringency conditions or a nucleotide sequence having at least about 75%sequence identity with SEQ ID NO:1 or its complementary form afteroptimal alignment may result in modulated expression. The term“modulation” is used to emphasize that, although transcription may beincreased or stabilised, this may have the effect of either permittingstabilized or enhanced translation of a product, or inducing transcriptdegradation such as via co-suppression, or post-transcriptional genesilencing.

To effect expression of the nucleotide sequence of the presentinvention, it may conveniently be incorporated into a chimeric geneticconstruct comprising inter alia one or more of the following: a promotersequence, a 5′ non-coding region, a cis-regulatory region such as afunctional binding site for transcriptional regulatory protein ortranslational regulatory protein, an upstream activator sequence, anenhancer element, a silencer element, a TATA box motif, a CCAAT boxmotif, an upstream open reading frame, transcriptional start site,translational start site, and/or nucleotide sequence which encodes aleader sequence, and a 3′ non-translated region. Preferable the chimericgenetic construct is designed for transformation of plants ashereinafter described.

The term “5′ non-coding region” is used herein in its broadest contextto include all nucleotide sequences which are derived from the upstreamregion of an expressible gene, other than those sequences which encodeamino acid residues which comprise the polypeptide product of said gene,wherein 5′ non-coding region confers or activates or otherwisefacilitates, at least in part, expression of the gene.

The term “gene” is used in its broadest context to include both agenomic DNA region corresponding to the gene as well as a cDNA sequencecorresponding to exons or a recombinant molecule engineered to encode afunctional form of a product.

As used herein, the term “cis-acting sequence” or “cis-regulatoryregion” or similar term shall be taken to mean any sequence ofnucleotides which is derived from an expressible genetic sequencewherein the expression of the first genetic sequence is regulated, atleast in part, by said sequence of nucleotides. Those skilled in the artwill be aware that a cis-regulatory region may be capable of activating,silencing, enhancing, repressing or otherwise altering the level ofexpression and/or cell-type-specificity and/or developmental specificityof any structural gene sequence.

Reference herein to a “promoter” is to be taken in its broadest contextand includes the transcriptional regulatory sequences of a classicalgenomic gene, including the TATA box which is required for accuratetranscription initiation, with or without a CCAAT box sequence andadditional regulatory elements (i.e. upstream activating sequences,enhancers and silencers) which alter gene expression in response todevelopmental and/or environmental stimuli, or in a tissue-specific orcell-type-specific manner. A promoter is usually, but not necessarily,positioned upstream or 5′, of a structural gene, the expression of whichit regulates. Furthermore, the regulatory elements comprising a promoterare usually positioned within 2 kb of the start site of transcription ofthe gene.

In the present context, the term “promoter” is also used to describe asynthetic or fusion molecule, or derivative which confers, activates orenhances expression of a structural gene or other nucleic acid molecule,in a plant cell. Preferred promoters according to the invention maycontain additional copies of one or more specific regulatory elements tofurther enhance expression in a cell, and/or to alter the timing ofexpression of a structural gene to which it is operably connected.

The term “operably connected” or “operably linked” in the presentcontext means placing a structural gene under the regulatory control ofa promoter, which then controls the transcription and optionallytranslation of the gene. In the construction of heterologouspromoter/structural gene combinations, it is generally preferred toposition the genetic sequence or promoter at a distance from the genetranscription start site that is approximately the same as the distancebetween that genetic sequence or promoter and the gene it controls inits natural setting, i.e. the gene from which the genetic sequence orpromoter is derived. As is known in the art, some variation in thisdistance can be accommodated without loss of function. Similarly, thepreferred positioning of a regulatory sequence element with respect to aheterologous gene to be placed under its control is defined by thepositioning of the element in its natural setting, i.e. the genes fromwhich it is derived.

Promoter sequences contemplated by the present invention may be nativeto the host plant to be transformed or may be derived from analternative source, where the region is functional in the host plant.Other sources include the Agrobacterium T-DNA genes, such as thepromoters for the biosynthesis of nopaline, octapine, mannopine, orother opine promoters; promoters from plants, such as the ubiquitinpromoter; tissue specific promoters (see, e.g. U.S. Pat. No. 5,459,252;International Patent Publication No. WO 91/13992); promoters fromviruses (including host specific viruses), or partially or whollysynthetic promoters. Numerous promoters that are functional in mono- anddicotyledonous plants are well known in the art (see, for example,Greve, 1983; Salomon et al., 1984; Garfinkel et al., 1983; Barker etal., 1983); including various promoters isolated from plants (such asthe Ubi promoter from the maize ubi-1 gene, e.g. U.S. Pat. No.4,962,028) and viruses (such as the cauliflower mosaic virus promoter,CaMV 35S).

The promoter sequences may include regions which regulate transcription,where the regulation involves, for example, chemical or physicalrepression or induction (e.g. regulation based on metabolites, light, orother physicochemical factors; see, e.g. International PatentPublication No. WO 93/06710 disclosing a nematode responsive promoter)or regulation based on cell differentiation (such as associated withleaves, roots, seed, or the like in plants; see, e.g. U.S. Pat. No.5,459,252 disclosing a root-specific promoter). Thus, the promoterregion, or the regulatory portion of such region, is obtained from anappropriate gene that is so regulated. For example, the 1,5-ribulosebiphosphate carboxylase gene is light-induced and may be used fortranscriptional initiation. Other genes are known which are induced bystress, temperature, wounding, pathogen effects, etc.

The chimeric genetic construct of the present invention may alsocomprise a 3′ non-translated sequence. A 3′ non-translated sequencerefers to that portion of a gene comprising a DNA segment that containsa polyadenylation signal and any other regulatory signals capable ofeffecting mRNA processing or gene expression. The polyadenylation signalis characterized by effecting the addition of polyadenylic acid tractsto the 3′ end of the mRNA precursor. Polyadenylation signals arecommonly recognized by the presence of homology to the canonical form 5′AATAAA-3′ although variations are not uncommon.

The 3′ non-translated regulatory DNA sequence preferably includes fromabout 50 to 1,000 nucleotide base pairs and may contain planttranscriptional and translational termination sequences in addition to apolyadenylation signal and any other regulatory signals capable ofeffecting mRNA processing or gene expression. Examples of suitable 3′non-translated sequences are the 3′ transcribed non-translated regionscontaining a polyadenylation signal from the nopaline synthase (nos)gene of Agrobacterium tumefaciens (Bevan et al., 1983) and theterminator for the T7 transcript from the octopine synthase gene ofAgrobacterium tumefaciens. Alternatively, suitable 3′ non-translatedsequences may be derived from plant genes such as the 3′ end of theprotease inhibitor I or II genes from potato or tomato, the soybeanstorage protein genes and the pea E9 small sub-unit of theribulose-1,5-bisphosphate carboxylase (ssRUBISCO) gene, although other3′ elements known to those of skill in the art can also be employed.Alternatively, 3′ non-translated regulatory sequences can be obtained denovo as, for example, described by An (1987), which is incorporatedherein by reference.

Accordingly, a further aspect of the present invention is directed to amethod for altering the phenotype of a plant, said method comprisingintroducing into the genome of one or more cells of a plant or one ormore cells of a parent of said first-mentioned plant a chimeric geneticconstruct comprising a nucleotide sequence substantially as set forth inSEQ ID NO:1 or a variant or homolog thereof including a nucleotidesequence having at least about 75% identity to SEQ ID NO:1 after optimalalignment or a nucleotide sequence capable of hybridizing to SEQ ID NO:1or its complementary form under low stringency conditions.

Even still another aspect of the present invention is directed to avector in the form of a chimeric construct comprising a nucleic acidmolecule having a nucleotide sequence substantially as set forth in SEQID NO:1 or a variant or homolog thereof including a nucleotide sequencehaving at least about 75% identity to SEQ ID NO:1 after optimalalignment or a nucleotide sequence capable of hybridizing to SEQ ID NO:1or its complementary form under low stringency conditions.

Yet another aspect of the present invention provides a chimeric geneticconstruct comprising a nucleic acid molecule comprising a nucleotidesequence substantially as set forth in SEQ ID NO:1 or a variant orhomolog thereof including a nucleotide sequence having at least about75% identity to SEQ ID NO:1 after optimal alignment or a nucleotidesequence capable of hybridizing to SEQ ID NO:1 or its complementary formunder low stringency conditions.

A chimeric genetic construct can also be introduced into a vector, suchas a plasmid. Plasmid vectors include additional DNA sequences thatprovide for easy selection, amplification, and transformation of theexpression cassette in prokaryotic and eukaryotic cells, e.g.pUC-derived vectors, pSK-derived vectors, pGEM-derived vectors,pSP-derived vectors, or pBS-derived vectors. Additional DNA sequencesinclude origins of replication to provide for autonomous replication ofthe vector, selectable marker genes, preferably encoding antibiotic orherbicide resistance, unique multiple cloning sites providing formultiple sites to insert DNA sequences or genes encoded in the chimericgenetic construct, and sequences that enhance transformation ofprokaryotic and eukaryotic cells.

The vector preferably contains an element(s) that permits either stableintegration of the vector or a chimeric genetic construct containedtherein into the host cell genome, or autonomous replication of thevector in the cell independent of the genome of the cell. The vector, ora construct contained therein, may be integrated into the host cellgenome when introduced into a host cell. For integration, the vector mayrely on a foreign or endogenous DNA sequence present therein or anyother element of the vector for stable integration of the vector intothe genome by homologous recombination. Alternatively, the vector maycontain additional nucleic acid sequences for directing integration byhomologous recombination into the genome of the host cell. Theadditional nucleic acid sequences enable the vector or a constructcontained therein to be integrated into the host cell genome at aprecise location in the chromosome. To increase the likelihood ofintegration at a precise location, the integrational elements shouldpreferably contain a sufficient number of nucleic acids, such as 100 to1,500 base pairs, preferably 400 to 1,500 base pairs, and mostpreferably 800 to 1,500 base pairs, which are highly homologous with thecorresponding target sequence to enhance the probability of homologousrecombination. The integrational elements may be any sequence that ishomologous with the target sequence in the genome of the host cell.Furthermore, the integrational elements may be non-encoding or encodingnucleic acid sequences.

For cloning and sub-cloning purposes, the vector may further comprise anorigin of replication enabling the vector to replicate autonomously in ahost cell such as a bacterial cell. Examples of bacterial origins ofreplication are the origins of replication of plasmids pBR322, pUC19,pACYC177, and pACYC184 permitting replication in E. coli, and pUB110,pE194, pTA1060, and pAMβ1 permitting replication in Bacillus. The originof replication may be one having a mutation to make its functiontemperature-sensitive in a Bacillus cell (see, e.g. Ehrlich, 1978).

Accordingly, another aspect of the present invention contemplates amethod for generating a plant with altered tissue architecture, saidmethod comprising introducing into the genome of one or more cells ofsaid plant or one or more cells of a parent of said first-mentionedplant a nucleic acid molecule comprising a nucleotide sequence encoding,or a sequence complementary to a nucleotide sequence encoding, an aminoacid sequence set forth in SEQ ID NO:2 or a derivative thereof includingan amino acid sequence having at least about 75% identity to SEQ ID NO:2after optimal alignment and then regenerating a plant from said plantcells to produce a plant with said altered tissue architecture andoptionally generating a progeny plant with said altered tissuearchitecture from said regenerated plant.

In a related aspect, there is contemplated a method for modifying planttissue architecture, said method comprising introducing into the genomeof one or more cells of said plant or one or more cells of a parent ofsaid first-mentioned plant a nucleic acid molecule comprising anucleotide sequence encoding, or a sequence complementary to anucleotide sequence encoding, an amino acid sequence set forth in SEQ IDNO:2 or a derivative thereof including an amino acid sequence having atleast about 75% identity to SEQ ID NO:2 after optimal alignment.

In work leading up to the present invention, the inventors sought todevise more efficacious methods for identifying the functions of thevast number of genetic sequences now available. In so doing, theydeveloped binary vectors and chimeric genetic constructs to enable therapid production of transgenic plants containing either sense orantisense copies of sequences of potentially-useful but unknownfunctions (Mylne and Botella, 1998).

In a most preferred embodiment, the chimeric genetic construct comprisesthe nucleotide sequence having the Genbank Accession Number T20918.

To facilitate identification of transformed cells, the vector desirablycomprises a further genetic construct comprising a selectable orscreenable marker gene. The actual choice of a marker is not crucial aslong as it is functional (i.e. selective) in combination with the plantcells of choice. The marker gene and the nucleotide sequence of interestdo not have to be linked, since co-transformation of unlinked genes as,for example, described in U.S. Pat. No. 4,399,216 is also an efficientprocess in plant transformation.

Included within the terms selectable or screenable marker genes aregenes that encode a “secretable marker” whose secretion can be detectedas a means of identifying or selecting for transformed cells. Examplesinclude markers that encode a secretable antigen that can be identifiedby antibody interaction, or secretable enzymes that can be detected bytheir catalytic activity. Secretable proteins include, but are notrestricted to, proteins that are inserted or trapped in the cell wall(e.g. proteins that include a leader sequence such as that found in theexpression unit of extensin or tobacco PR-S); small, diffusible proteinsdetectable, for example, by ELISA; and small active enzymes detectablein extracellular solution such as, for example, α-amylase, β-lactamase,phosphinothricin acetyltransferase).

Examples of bacterial selectable markers are the dal genes from Bacillussubtilis or Bacillus licheniformis, or markers that confer antibioticresistance such as ampicillin, kanamycin, erythromycin, chloramphenicolor tetracycline resistance. Exemplary selectable markers for selectionof plant transformants include, but are not limited to, a hyg gene whichencodes hygromycin B resistance; a neomycin phosphotransferase (neo)gene conferring resistance to kanamycin, paromomycin, G418 and the likeas, for example, described by Potrykus et al. (1985); aglutathione-S-transferase gene from rat liver conferring resistance toglutathione derived herbicides as, for example, described in EP-A 256223; a glutamine synthetase gene conferring, upon overexpression,resistance to glutamine synthetase inhibitors such as phosphinothricinas, for example, described International Patent Publication No. WO87/05327, an acetyl transferase gene from Streptomyces viridochromogenesconferring resistance to the selective agent phosphinothricin as, forexample, described in European Patent Application No. EP-A 275 957, agene encoding a 5-enolshikimate-3-phosphate synthase (EPSPS) conferringtolerance to N-phosphonomethylglycine as, for example, described byHinchee et al. (1988), a bar gene conferring resistance againstbialaphos as, for example, described in International Patent PublicationNo. WO 91/02071; a nitrilase gene such as bxn from Klebsiella ozaenaewhich confers resistance to bromoxynil (Stalker et al., 1988); adihydrofolate reductase (DHFR) gene conferring resistance tomethotrexate (Thillet et al., 1988); a mutant acetolactate synthase gene(ALS), which confers resistance to imidazolinone, sulfonylurea or otherALS-inhibiting chemicals (European Patent Application No. EP-A-154 204);a mutated anthranilate synthase gene that confers resistance to 5-methyltryptophan; or a dalapon dehalogenase gene that confers resistance tothe herbicide.

Preferred screenable markers include, but are not limited to, a uidAgene encoding a β-glucuronidase (GUS) enzyme for which variouschromogenic substrates are known; a β-galactosidase gene encoding anenzyme for which chromogenic substrates are known; an aequorin gene(Prasher et al., 1985), which may be employed in calcium-sensitivebioluminescence detection; a green fluorescent protein gene (Niedz etal., 1995); a luciferase (luc) gene (Ow et al., 1986), which allows forbioluminescence detection; a β-lactamase gene (Sutcliffe, 1978), whichencodes an enzyme for which various chromogenic substrates are known(e.g. PADAC, a chromogenic cephalosporin); an R-locus gene, encoding aproduct that regulates the production of anthocyanin pigments (redcolour) in plant tissues (Dellaporta et al., 1988); an α-amylase gene(Ikuta et al., 1990); a tyrosinase gene (Katz et al., 1983) whichencodes an enzyme capable of oxidizing tyrosine to dopa and dopaquinonewhich in turn condenses to form the easily detectable compound melanin;or a xylE gene (Zukowsky et al., 1983), which encodes a catecholdioxygenase that can convert chromogenic catechols.

A further aspect of the present invention provides a transfected ortransformed cell, tissue, or organ which comprises a nucleotide sequencesubstantially as set forth in SEQ ID NO:1 or a variant or homologthereof including a nucleotide sequence having at least about 75%identity to SEQ ID NO:1 after optimal alignment or a nucleotide sequencecapable of hybridizing to SEQ ID NO:1 or its complementary form underlow stringency conditions.

The vectors and chimeric genetic construct(s) of the present inventionmay be introduced into a cell by various techniques known to thoseskilled in the art. The technique used may vary depending on the knownsuccessful techniques for that particular organism.

Techniques for introducing vectors, chimeric genetic constructs and thelike into cells include, but are not limited to, transformation usingCaCl₂ and variations thereof, direct DNA uptake into protoplasts,PEG-mediated uptake to protoplasts, microparticle bombardment,electroporation, microinjection of DNA, microparticle bombardment oftissue explants or cells, vacuum-infiltration of tissue with nucleicacid, and T-DNA-mediated transfer from Agrobacterium to the planttissue.

For microparticle bombardment of cells, a microparticle is propelledinto a cell to produce a transformed cell. Any suitable ballistic celltransformation methodology and apparatus can be used in performing thepresent invention. Exemplary apparatus and procedures are disclosed byStomp et al. U.S. Pat. No. 5,122,466) and Sanford and Wolf (U.S. Pat.No. 4,945,050). When using ballistic transformation procedures, thegenetic construct may incorporate a plasmid capable of replicating inthe cell to be transformed.

Examples of microparticles suitable for use in such systems include 0.1to 10 μm and more particularly 10.5 to 5 μm tungsten or gold spheres.The DNA construct may be deposited on the microparticle by any suitabletechnique, such as by precipitation.

Plant tissue capable of subsequent clonal propagation, whether byorganogenesis or embryogenesis, may be transformed with a chimericgenetic construct of the present invention and a whole plant generatedtherefrom. The particular tissue chosen will vary depending on theclonal propagation systems available for, and best suited to, theparticular species being transformed. Exemplary tissue targets includeleaf disks, pollen, embryos, cotyledons, hypocotyls, megagametophytes,callus tissue, existing meristematic tissue (e.g. apical meristem,axillary buds, and root meristems), and induced meristem tissue (e.g.cotyledon meristem and hypocotyl meristem).

The regenerated transformed plants may be propagated by a variety ofmeans, such as by clonal propagation or classical breeding techniques.For example, a first generation (or T1) transformed plant may be selfedto give homozygous second generation (or T2) transformant, and the T2plants further propagated through classical breeding techniques.

Accordingly, in another aspect of the present invention, there isprovided a method for modifying plant tissue architecture, said methodcomprising introducing into the genome of one or more cells of saidplant or one or more cells of a parent of said first-mentioned plant anucleic acid molecule comprising a nucleotide sequence substantially asset forth in SEQ ID NO:1 or a variant or homolog thereof including anucleotide sequence having at least about 75% identity to SEQ ID NO:1after optimal alignment or a nucleotide sequence capable of hybridizingto SEQ ID NO:1 or its complementary form under low stringencyconditions.

In a related embodiment, the present invention provides a method formodifying plant tissue architecture, said method comprising introducinginto the genome of one or more cells of said plant or one or more cellsof a parent of said first-mentioned plant a vector comprising a chimericgenetic construct comprising a nucleotide sequence substantially as setforth in SEQ ID NO:1 or a variant or homolog thereof or a nucleotidesequence having at least about 75% identity to SEQ ID NO:1 after optimalalignment or a nucleotide sequence capable of hybridizing to SEQ ID NO:1or its complementary form under low stringency conditions and thenregenerating a plant from said plant cells to produce a plant withmodified tissue architecture.

Accordingly, this aspect of the present invention, insofar as it relatesto plants, further extends to progeny of the plants engineered toexpress a nucleotide sequence set forth in SEQ ID NO:1 or a variant orhomolog thereof or a nucleotide sequence capable having at least about75% identity to SEQ ID NO:1 after optimal alignment or a nucleotidesequence capable of hybridizing to SEQ ID NO:1 or its complementary formunder low stringency conditions, as well as vegetative, propagative andreproductive parts of the plants, such as flowers (including cut orsevered flowers), parts of plants, fibrous material from plants (forexample, cotton) and reproductive portions including cuttings, pollen,seeds and callus.

Another aspect of the present invention provides a genetically modifiedplant cell or multicellular plant or progeny thereof or parts of saidtransgenic plant having an altered phenotype compared to itsnon-transformed equivalent, wherein said transgenic plant comprises thenucleotide sequence substantially as set forth in SEQ ID NO:1 or avariant or homolog thereof or a nucleotide sequence having at leastabout 75% identity to SEQ ID NO:1 or its complementary form under lowstringency conditions.

More particularly, the present invention provides a genetically modifiedplant cell or multicellular plant or progeny or parts thereof comprisinga nucleic acid molecule comprising a nucleotide sequence encoding or asequence complementary to a nucleotide sequence encoding an amino acidsequence set forth in SEQ ID NO:2 or a derivative thereof or an aminoacid sequence having at least about 75% identity to SEQ ID NO:2 afteroptimal alignment.

Even more particularly, the present invention provides a plant cell ormulticellular plant or progeny thereof wherein said cell, plant, progenyor part thereof exhibits altered tissue architecture compared to itsnon-transformed equivalent.

The term “genetically modified” is used in its broadest sense andincludes introducing gene(s) into cells, mutating gene(s) in cells andaltering or modulating the regulation of gene(s) in cells. In thecontext of the present invention, a transgenic cell or plant line mayalso be considered as a mutant cell or plant line when compared with itsnon-transgenic counterpart.

Still another aspect of the present invention is directed to the use ofa nucleic acid molecule comprising a nucleotide sequence substantiallyas set forth in SEQ ID NO:1 or a variant or homolog thereof including anucleotide sequence having at least about 75% identity to SEQ ID NO:1after optimal alignment or a nucleotide sequence capable of hybridizingto SEQ ID NO:1 or its complementary form under low stringency conditionsin the manufacture of a transgenic plant having tissues with alteredphenotype.

The present invention is further described by the following non-limitingExamples.

EXAMPLE 1 Preparation of Binary Vectors

An expression cassette for driving expression of chimeric constructs,which included a range of different ESTs of unknown functions, wasgenerated by separately excising the CaMV35S promoter and the nos 3′terminator region from pBI121 (Bevan, 1984) and ligating them into thepUC18 multiple cloning site. This CaMV35S-polylinker-nos cassette wascloned into a binary vector backbone containing a Basta (registeredtrademark) resistance gene (bar) and a poly-linker (pSLJ75515, see Joneset al., 1992), which had previously had superfluous restriction enzymesites removed. This binary vector was named, pAOV, and would become thebackbone for the pSOV2 vector used to produce the plentiful phenotype(Mylne and Botella, 1998).

The multiple cloning site of pSOV2 was created by removing the cDNAclone insert of a PRL-2 clone (Newman et al., 1994) using SalI and NotI.The ends of the vector were blunt ended and the vector religated. Theresulting plasmid (pZLD) is essentially pZL1 (D'Alessio et al., 1992)missing the restriction sites from SalI to NotI. The pZLD multiplecloning site was amplified by PCR using T7 and M13 primers and ligatedinto pAOV that had been previously modified to remove severalconflicting restriction sites.

The pSOV2 binary vector was designed to allow the cloning of ESTsequences from the Arabidopsis PRL-2 library in sense orientation. Thepurpose of this vector was the production of plants with extra copies ofa particular gene to achieve either over-expression of the encodedprotein or the overall down regulation of the gene by co-suppressionevents. EST sequences can be cloned using the PstI or EcoRI site at the5′ end of the EST clone and the XbaI, BamHI or HindIII sites at the 3′end. There are no spurious ATG codons in pSOV2 that could interfere withthe start of translation of the encoded protein.

EST clones destined for pSOV2 were digested initially with BamHI andEcoRI and if any cut internally, they were digested with PstI, XbaI andHindIII until a suitable combination of enzymes was found that couldachieve an asymmetric ligation. The plentiful EST was sub-cloned intopSOV2 using BamHI and EcoRI.

EXAMPLE 2 Transformation and Regeneration of Arabidopsis

A total of 89 EST clones were selected for use in binary vectors, 67 forthe anti-sense strategy (destined for pAOV binary vector) and 22 for thesense over-expression strategy (destined for pSOV2 binary vector). Basedon putative function, 77% of the ESTs for the anti-sense strategy (52)putatively belonged to the protein kinase family and the remaining 23%(15) were of unknown function. Sixty percent (13) of the full-lengthESTs selected for the sense strategy were of unknown function. Theremaining 9 were comprised of 6 putative protein kinases and 3 putativeprotein phosphatases.

Binary vectors were tri-parental mated into Agrobacterium tumefaciens(strain LBA4404) (Svab, Hajdukiewicz and Maliga, 1995) and theAgrobacterium suspension was used to transform adult Arabidopsis plantsgrown in soil pots (Bechtold, Ellis and Pelletier, 1993). Selection oftransgenic plantlets was performed by sowing approximately 0.5 ml ofseeds from infiltrated plants in soil trays (260 mm×310 mm). Germinationwas synchronized by treatment at 4° C. for 3-5 days. Trays were placedunder long-day light at 21° C. and seedlings sprayed first uponemergence and twice afterwards at 3-day intervals with 0.4% Basta(registered trademark) (active constituent 20% glufosinate ammonium;Hoechst Schering Agrevo GmbH). Basta-resistant plants were transferredto pots and grown to maturity. Plants were observed during growth forthe presence of altered phenotypes.

EXAMPLE 3 Identification of Expressed Sequence Tag (EST)

One particularly useful phenotype, designated plentiful, was found tohave been generated upon introduction, in the sense direction, of theEST having Genbank Accession Number T20918. This EST had been derivedfrom PRL-2 cDNA library (Newman et al., 1994, Plant Physiology 106(4):1241), ordered from the Arabidopsis Information Management Service andsupplied by the Arabidopsis Biological Resource Center (ABRC) at OhioState University, U.S.A., as Clone_ID: 89I24T7. These plants wereselected for further investigation.

EXAMPLE 4 Analysis of T2 Arabidopsis Plantlets

Co-Segregation of the Phenotype with Basta (Registered Trademark)Resistance

To prove that the transgene was responsible for the phenotype, T₂ seedwas sown on soil and at three weeks, leaves of all T₂ plants werepainted with 0.08% Basta (registered trademark) (active constituent 20%glufosinate ammonium) and scored for their response to Basta two dayslater. The results of this analysis are presented in Table 1, below:

TABLE 1 Co-segregation of the plentiful phenotype with the Basta(registered trademark) transgene Basta Resistant Basta Sensitive LineMutant Wild Mutant Wild Co-seg Ratio R:S 116-04 79 0 0 16 100% 4.4:1 116-05 115 0 0 8 100% 15:1 

EXAMPLE 5 Northern Analyses

RNA for the multi-tissue Northern and transgenic Northern of seedlingtissue (FIGS. 1 and 2) was extracted as by (Etheridge et al., 1999). TheLiCl supernatent from this method contained the genomic DNA used for theSouthern blot analysis (FIG. 4). RNA for the multi-tissue transgenicNorthern (FIG. 3) was prepared by the following method. Small amounts offrozen tissue were ground into a fine powder and vortexed for 1 min in amixture of 0.5 ml of 100 mM Tris-HCl (pH 8.0) containing 100 mM NaCl, 5mM EDTA, 0.5% w/v SDS and 0.5 ml of phenol/chloroform/isoamyl alcohol(25:24:1). This mixture was centrifuged and 400 μl of the aqueous phaseadded to 800 μl of ethanol to precipitate the nucleic acids. Aftercentrifugation for 5 min, the total nucleic acid pellet was dried andresuspended in 50 μl of water.

RNA was fractionated on a 1% w/v agarose (0.5×TBE) gel and transferredto a nylon membrane by capillary blotting and probing with ³²P-labeledfragment using standard laboratory techniques (Sambrook et al., 1989).

-   -   (a) Northern analysis of wild-type gene expression showed that        plentiful gene expression was highest in open flowers and roots        (refer to FIG. 1). This suggested that the phenotype must be        caused by expression of this tissue-specific message, throughout        all tissues, at greatly elevated levels.    -   (b) To prove that the CaMV35S promoter was driving        over-expression of the plentiful transcript, total RNA was        extracted from 3 wild-type lines and two independent transgenic        plentiful lines (lines 4B and 5D) and examined by Northern        analysis. The autoradiography clearly showed that there was        over-expression of the plentiful transcript in both independent        transgenic lines.    -   (c) To prove that the CaMV35S promoter was driving constitutive        over-expression of the plentiful transcript, total RNA was        extracted from different tissues of wild-type and plentiful line        5D. The autoradiograph of the Northern blot, probed with the        plentiful gene fragment clearly shows the over-expression of the        transcript in all the plentiful tissues tested. Wild-type        expression is not visible as expected, considering the low        expression levels of the plentiful transcript. By contrast, the        CaMV35S-driven over-expression in the plentiful line is easily        detectable.

EXAMPLE 6 Southern Analyses of Independent Transformation Events

To demonstrate that the phenotype did not arise from an insertion event(independent transformation), 3 μg of genomic DNA from wild-type plantsand two lines displaying the plentiful phenotype was digested with oneof EcoRI, HindIII and SalI. The digested DNA was electrophoresed andtransferred to a nylon membrane. The membrane was probed with³²P-labeled 35S probe (see FIG. 4A). The Southern blot probed with the35S promoter shows that lines 116-4B and 116-5D contain both singleinsertions of the T-DNA. As expected, no hybridization of the 35S probedwas detected in wild-type (WT) DNA. This Southern blot clearly showsthat these two transgenics lines arise from independent transformationevents.

The membrane was then stripped and rehybridized to a plentiful EST probe(see FIG. 4B). The Southern blot probed with the plentiful EST probeshould detect both the wild-type copy of the gene and the additionalcopy of the plentiful gene included in the transferred T-DNA. Digestionof the plentiful EST clone with EcoRI, HindIII and SalI shows that itcontains and internal HindIII site (FIG. 5). HindIII cuts once insidethe gene sequence and once in the polylinker of pZL1, outside the 3′ endof the gene. When transferred to pSOV2, the HindIII site of pSOV2 willproduce the same 500 bp band upon digestion of the pSOV2-116 senseconstruct. The HindIII lanes of the Southern blot show DNA from bothtransgenics liberate a 500 bp homologous to the plentiful EST probe.

Combined, these Southern blots confirm that the plentiful transgenicscontain the correct T-DNA region of the pSOV2-116 binary construct andthat the phenotype did not arise from an insertion event.

EXAMPLE 7 Description of Resulting Phenotype

The selected plants exhibited a number of characteristic upon which theycould be distinguished from their non-transgenic equivalents, including:altered aerial architecture, alterations in leaf number and morphology,and increase in the thickness of organs, alteration in silique numbersand morphology and a delay in development.

Aerial Architecture

There was a significant difference between the general architecture ofwild-type and that of plentiful phenotype. This difference wasconsistent throughout the plant in primary bolts, primary lateralbranches, secondary lateral branches and secondary bolts produced.Plants displaying the plentiful phenotype were generally smaller andmore compact resembling a wild-type plant that had been compressed.Bolts and lateral branches were shorter and branches were placed closertogether (smaller intemodal distance). Branches were positioned closerto the base of the bolt (or branch in the case of secondary branches)and a larger number of secondary lateral branches were produced.Similarly, the first silique in plentiful plants was closer to the baseof the bolt (or branch). All these features gave plentiful plants abushy appearance.

Both wild-type and plentiful plants produced roughly the same number ofprimary lateral branches. However, differences emerge when secondarylateral branches are examined. ‘Plentiful’ plants consistently produceda larger number of cauline leaves and secondary lateral branches thanthe wild-type. ‘Plentiful’ plants tended to extend secondary lateralbranch primordia generally from later cauline leaf positions whereas thewild-type tended to extend primordia earlier.

TABLE 2 Comparison of general bolt and branch architecture of‘Plentiful’ plants and non-transformed segregants (NTS) NTS 116-5DPrimary bolt height 347.67 ± 0.09  238.47 ± 2.91  (mm ± standard error)Average number of primary lateral 3.60 ± 0.11 3.59 ± 0.13 branchesAverage number of secondary 4.23 ± 0.36 5.59 ± 0.38 lateral branchesLeaves

The rosette leaves of the plentiful plant differed significantly fromthe wild-type in all three characteristics examined (see Table 3). Themost noticeable difference was leaf length, where plentiful averages 8mm shorter than wild-type. This decrease when coupled with an increasein leaf width produced rosette leaves that were rounder, almost square,compared with wild-type rosette leaves that had typical elongated ovalshapes. ‘Plentiful’ rosette leaves had a shorter petiole length and theconnection between the rosette leaf and petiole was less tapered.‘Plentiful’ also produced a larger number of rosette leaves. Together,these alterations created a rosette that was smaller and more compactthan the wild-type. In addition to showing a dark green colour, therosette leaves were more rigid than the wild-type perhaps due to anincrease in leaf thickness or compactness.

TABLE 3 Comparison of rosette leaf dimensions of plentiful andnon-transformed segregants (NTS) (average mm ± std. deviation, n = 29)NTS 116-5D Petiole Length  9.71 ± 0.51  7.00 ± 0.54 Leaf Length 26.09 ±2.06 18.19 ± 0.99 Leaf Width 14.87 ± 0.81 18.28 ± 0.91Organ Thickness

‘Plentiful’ plants have thicker organs than wild-type plants.Measurements suggest an average increase of 16.5% in organ thickness forplentiful plants.

TABLE 4 Organ thickness of wild-type and plentiful plants (Line 116-5D)in average mm ± standard error NTS 116-5D % Increase Primary Bolt 1.20 ±0.04 1.32 ± 0.02 9.5 Lateral Branch 1 0.97 ± 0.04 1.04 ± 0.02 7.5Lateral Branch 2 0.87 ± 0.03 1.10 ± 0.10 27.0 Lateral Branch 3 0.80 ±0.04 0.92 ± 0.03 16.3 Lateral Branch 4 0.77 ± 0.06 0.92 ± 0.06 19.5Silique 0.58 ± 0.03 0.69 ± 0.02 19.3Siliques

The inflorescence meristem of plentiful produced siliques that did notmove from the inflorescence apex as quickly as the wild-type. Thesiliques were more closely spaced, had a shorter petiole and wereshorter than the wild-type. These characteristics gave inflorescences a‘bristly’ appearance. The siliques of both wild-type and plentifulplants held a variable number of seeds and were not significantlydifferent (58.31±3.33 and 58.33±1.16 respectively). ‘Plentiful’ siliqueswere fatter and had a bumpier surface compared to wild-type siliques.The phyllotactic angles of siliques of NTS and plentiful plants weresignificantly different with an angle of 148.960° (degrees)±1.80 and131.42±1.93, respectively. Plentiful plants produced more siliques thanthe wild-type in all locations studied and by total silique number(233±5.69 for plentiful vs. 211±9.36 for wild-type) The distribution ofsiliques on plentiful plants was similar to that of the wild-type.

TABLE 5 Silique measurements on different parts of wild-type andplentiful Arabidopsis (line 116-5D). Values are average mm ± standarderror. Primary Lateral Bolt Branch Secondary Bolt NTS 116-5D NTS 116-5DNTS 116-5D Silique 7.95 ± 0.19 5.53 ± 0.15 6.50 ± 0.10 5.46 ± 0.10 6.00± 0.12 4.18 ± 0.21 petiole length Silique length 14.26 ± 0.68  10.16 ±0.19  13.53 ± 0.35  10.12 ± 0.13  12.39 ± 0.43  9.03 ± 0.17Inter-silique 10.02 ± 0.80  6.48 ± 0.50 7.42 ± 0.52 5.94 ± 0.47 7.01 ±0.76 4.79 ± 0.79 distanceDevelopmental Timing

Plentiful has a longer vegetative stage showing an approximate delay of11 days for the transition to flowering. However, after bolting, theinflorescence meristem in plentiful and NTS plants develop at the samespeed (i.e. if plentiful plants were planted 11 days before NTS, nodifference would be observed in table below). The plentiful plants alsohave a significant difference in the time to senesce. Senescence wasattributed to plants when the first seed pod lost its green pigmentationand turned yellow. The outcome of this measurement was supported byimages of the rosette of wild-type and plentiful plants at 50 days. Therosette of the plentiful plant is still green while most of the rosetteof the wild-type plant has lost pigmentation and is clearly in the midto late stages of senescence (see FIG. 7).

FIG. 7 shows the difference in the stage of development at 50 days foradult plentiful plants and wild-type Arabidopsis plants. Plentiful isstill in the middle of the reproductive (flowering) phase while thewild-type Arabidopsis at the same stage has completed flowering. Theclose up of the rosettes of the whole plants in (A) above shows that thewild-type rosette leaves are in an advanced stage of senescence. Thewhite arrows pointing to dead leaves and chlorotic (yellowing) tissue.The loss of pigmentation in the wild-type plant (change from green toyellow) is difficult to visualize using a gray-scale colour scheme. Theabnormal ‘bumps’ in plentiful seed pods are shown compared to the smoothexterior of a wild-type Arabidopsis.

TABLE 6 Development of wild-type and Plentiful (Line 116-5D) in averagedays ± standard error NTS 116-5D Delay Days to bolting (4 cm bolt) 36.76± 0.22 47.30 ± 0.33 11 days  Days to 1st lateral branch 36.66 ± 0.1744.91 ± 0.29 8 days Days to 1st secondary bolt 38.55 ± 0.30 47.05 ± 0.329 days Days to 1st flower 37.00 ± 0.31 46.22 ± 0.47 9 days Days to 20thflower 44.46 ± 0.63 52.39 ± 0.33 8 days Days to senescence (1st yellow51.95 ± 0.33 60.97 ± 0.44 9 days silique)

EXAMPLE 8 Identity of Genetic Sequence Encoding the Plentiful Phenotype

The sequence for the plentiful phenotype (SEQ ID NO:1), in GCG format,is as shown below. Base-pairs of the sequence are numbered on theleft-hand side. Base-pairs 1-84=5′ untranslated region; 85-87=start ATG(bold); base-pairs 85-389=protein coding region; 391-393=stop TAA(bold); base-pairs 394-614=3′ untranslated region.

[SEQ ID NO:1] ATACTCTCAT ATATATTTGC ATCTAATCTT GTAAGCAAAC GTTATCACTTGTCTACACAA CATTCTTTCA TTTACAATAA TAATATGGGT GTAACATTAG AAGGACAAAGAAAGGAATCA ATTTGGGTTT TGATGAGAAG ACAAAGGGCT CGAAGGGCAC TTGTGAAGAAGATCATGATC CGACCAAGGA AGAGTGTAGA AGCTTCTAGA AGACCTTGTC GCGCAATACACAGACGAGTG AAGACGCTAA AAGAGCTTGT TCCCAACACC AAAACATCAG AAGGTTTAGATGGACTCTTT AGACAAACGG CAGATTATAT CTTGGCTTTG GAAATGAAAG TGAAAGTTATGCAGACAATG GTTCAGGTTT TGACCGAAAC TAACTGTGTT TAAAAGCCTT CATATATTTTTTGTATATCT TGTTGGATTT TACGTTCTTT TTAGTTTTTA TTTGTTCGTG TTTATTTTTTATTATCTCGT GTGATTGTCT TGTGTTGCTT ATATAGAAAA GGAATTTGGT TTATCTTGCTGCTGTAGACT ATGCAGAAAA TTAAATATCA AAAATATATA TGTATTATAT GCTTATCTAAATAACAGATG ACTGTTGGTT CGGC

Those skilled in the art will appreciate that the invention describedherein is susceptible to variations and modifications other than thosespecifically described. It is to be understood that the inventionincludes all such variations and modifications. The invention alsoincludes all of the steps, features, compositions and compounds referredto or indicated in this specification, individually or collectively, andany and all combinations of any two or more of said steps or features.

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1. A method for generating a plant with a modified plant phenotypecomprising introducing into the genome of one or more cells of saidplant a nucleic acid molecule comprising a nucleotide sequence encodingthe amino acid sequence set forth in SEQ ID NO:2 or the complementthereof, and then regenerating a plant from said plant cells to producea plant with said modified phenotype and optionally generating a progenyplant with said modified phenotype from said regenerated plant, whereinsaid progeny plant comprises the nucleic acid molecule and wherein saidmodified phenotype is selected from the group consisting of: smaller andmore compact stature, shorter bolt and lateral branches, smallerinternodal distance, branches positioned closer to the base of theplant, more lateral branches, more cauline leaves, leaves are shorterand wider, more rosette leaves, thicker leaves, more siliques, and alonger vegetative stage compared to a control plant.
 2. The method ofclaim 1, wherein the plant having a modified phenotype is theregenerated plant.
 3. The method of claim 1, wherein the plant having amodified phenotype is a progeny of said regenerated plant and whereinsaid progeny plant comprises said nucleic acid molecule.
 4. A method forfacilitating the modification of a plant phenotype comprisingintroducing into the genome of one or more cells of said plant a nucleicacid molecule comprising a nucleotide sequence encoding the amino acidsequence set forth in SEQ ID NO:2 or the complement thereof and whereinsaid phenotype is selected from the group consisting of: smaller andmore compact stature, shorter bolt and lateral branches, smallerinternodal distance, branches positioned closer to the base of theplant, more lateral branches, more cauline leaves, leaves are shorterand wider, more rosette leaves, thicker leaves, more siliques, and alonger vegetative stage compared to a control plant.
 5. The method ofclaim 4, further comprising regenerating a plant from the one or morecell of said plant, wherein the progeny of the regenerated plant has amodified phenotype and wherein said progeny comprises said nucleic acidmolecule.
 6. A method for altering the phenotype of a plant, said methodcomprising introducing into the genome of one or more cells of saidplant a nucleic acid molecule comprising a nucleotide sequence as setforth in SEQ ID NO:1, or the complement thereof wherein said alteredphenotype is selected from the group consisting of: smaller and morecompact stature, shorter bolt and lateral branches, smaller internodaldistance, branches positioned closer to the base of the plant, morelateral branches, more cauline leaves, leaves are shorter and wider,more rosette leaves, thicker leaves, more siliques, and a longervegetative stage compared to a control plant.
 7. The method of claim 6,wherein the nucleic acid molecule is comprised in a chimeric geneticconstruct.
 8. The method of claim 7, wherein the chimeric geneticconstruct is comprised in a vector.
 9. A method for generating a plantwith altered tissue architecture, said method comprising introducinginto the genome of one or more cells of said plant a nucleic acidmolecule comprising a nucleotide sequence encoding the amino acidsequence set forth in SEQ ID NO:2, or the complement thereof, and thenregenerating a plant from said plant cells to produce a plant with saidaltered tissue architecture and optionally generating a progeny plantwith said altered tissue architecture from said regenerated plant,wherein said progeny plant comprises the nucleic acid molecule andwherein said altered tissue architecture is selected from the groupconsisting of: changes in cell shape, changes in cellular developmentand changes in cell numbers.
 10. The method of claim 9, wherein theplant having altered tissue architecture is a regenerated plant.
 11. Themethod of claim 9, wherein the plant having altered tissue architectureis a progeny of said regenerated plant and wherein said progeny plantcomprises said nucleic acid molecule.
 12. A method for modifying planttissue architecture, said method comprising introducing into the genomeof one or more cells of said plant a nucleic acid molecule comprising anucleotide sequence encoding the amino acid sequence set forth in SEQ IDNO:2 or the complement thereof wherein said modifying tissuearchitecture is selected from the group consisting of: changes in cellshape, changes in cellular development and changes in cell numbers. 13.The method of claim 12, further comprising regenerating a plant from theplant cells having the introduced nucleotide sequence, wherein a progenyof the regenerated parent plant has modified tissue architecture andcomprises the introduced nucleic acid molecule.
 14. A method formodifying plant tissue architecture, said method comprising introducinginto the genome of one or more cells of said plant a nucleic acidmolecule comprising a nucleotide sequence as set forth in SEQ ID NO:1,or the complement thereof and wherein said modifying tissue architectureis selected from the group consisting of: changes in cell shape, changesin cellular development and changes in cell numbers.
 15. The methodaccording to claim 1, wherein the plant is a monocotyledonous plant. 16.The method according to claim 1, wherein the plant is a dicotyledonousplant.
 17. A genetically modified plant cell, plant, progeny thereof orparts of said genetically modified plant, generated in accordance withthe method of claim 1 which comprises a nucleotide sequence as set forthin SEQ ID NO:1, or the complement thereof.
 18. A genetically modifiedplant cell, plant, progeny or parts thereof generated in accordance withthe method of claim 1, comprising a nucleic acid molecule comprising anucleotide sequence encoding the amino acid sequence set forth in SEQ IDNO:2 or the complement thereof.
 19. The plant cell, plant, progeny orparts thereof of claim 17, wherein said cell, plant, progeny or partthereof exhibits altered tissue architecture compared to itsnon-transformed equivalent wherein said altered tissue architecture isselected from the group consisting of: changes in cell shape, changes incellular development and changes in cell numbers.
 20. The methodaccording to claim 4, wherein the plant is a monocotyledonous plant. 21.The method according to claim 6, wherein the plant is a monocotyledonousplant.
 22. The method according to claim 9, wherein the plant is amonocotyledonous plant.
 23. The method according to claim 12, whereinthe plant is a monocotyledonous plant.
 24. The method according to claim12, wherein the plant is a monocotyledonous plant.
 25. The methodaccording to claim 4, wherein the plant is a dicotyledonous plant. 26.The method according to claim 6, wherein the plant is a dicotyledonousplant.
 27. The method according to claim 9, wherein the plant is adicotyledonous plant.
 28. The method according to claim 12, wherein theplant is a dicotyledonous plant.
 29. The method according to claim 14,wherein the plant is a dicotyledonous plant.
 30. A genetically modifiedplant cell, plant, progeny thereof or parts of said genetically modifiedplant, generated in accordance with the method of claim 4 whichcomprises a nucleotide sequence as set forth in SEQ ID NO:1, or thecomplement thereof.
 31. A genetically modified plant cell, plant,progeny thereof or parts of said genetically modified plant, generatedin accordance with the method of claim 6 which comprises a nucleotidesequence as set forth in SEQ ID NO:1, or the complement thereof.
 32. Agenetically modified plant cell, plant, progeny thereof or parts of saidgenetically modified plant, generated in accordance with the method ofclaim 9 which comprises a nucleotide sequence as set forth in SEQ IDNO:1, or the complement thereof.
 33. A genetically modified plant cell,plant, progeny thereof or parts of said genetically modified plant,generated in accordance with the method of claim 12 which comprises anucleotide sequence as set forth in SEQ ID NO:1, or the complementthereof.
 34. A genetically modified plant cell, plant, progeny thereofor parts of said genetically modified plant, generated in accordancewith the method of claim 14 which comprises a nucleotide sequence as setforth in SEQ ID NO:1, or the complement thereof.